1. Field of the Invention
The problem which the present invention specifically is intended to solve is in present installations of oil and/or gas well pumps.
A typical oil or gas well pump is self-propelled in the sense that the fluid which is being pumped is also burned in the internal combustion engine which drives the pump. The engine is generally of the reciprocating type, and comprises a single, large cylinder which drives the pump at very low RPM through a large flywheel. To promote efficient operation, the exhaust gas from the reciprocating engine is ordinarily expanded through a turbine which in turn drives a compressor for the purpose of supplying supercharging air to the pump engine. Before the exhaust gases pass to the turbine, large particles (generally in excess of 0.50 inch) are removed by passing the gas through a filter. It is this filter which is the subject of the present invention.
2. Description of the Prior Art
Since oil or gas pumps frequently must operate in isolated locations, without human attention, and almost always on a twenty-four hour basis, reliability is extremely important. In the prior art, the filter element in the stream of exhaust gases from the pump engine suffered from an undesirably high rate of failure. This was caused both by high temperatures (upwards of 1400.degree.F.) and by fluctuating temperatures from the alternating presence and absence of exhaust gas flow through the filter.
In the prior art filter design which the present invention replaces, the filter element was located at the flange end of of the housing (see FIG. 7) and the filter element comprised a corrugated, spirally wound assembly. This arrangement was poor from an expansion standpoint and at high temperatures distortion of the filter element would occur along the axis of the cylindrical housing, i.e., -- bulging.
Specifically in the prior art, the spiral design of the filter element and the location of the filter element interiorly of the mounting flange, severely inhibited normal expansion of the filter element in the radial direction with variations in temperature. Since the filter element could not expand sufficiently in a radial direction, bulging would occur in a longitudinal direction. The stresses caused by the inhibited radial expansion and resultant bulging would often lead to cracking and premature failure of the filter element or housing.
The filter of the present invention is so constructed and arranged as to overcome this bulging problem by allowing virtually free radial expansion of the filter element and to provide an extremely reliable long lasting filter which will function efficiently, without maintenance or attention of any kind, in unattended oil or gas well pump installations.